While the largest school district in the county is poised to lay off more than 1,650 of its teachers, 24 other school districts will head into the 2012-13 school year without issuing a single pink slip.

San Diego County officials on Friday said that nearly 2,200 teachers in the region will receive layoff warnings, about one out of every 10 public school teachers in the region. The cuts are being made as districts deal with a fifth year of state budget troubles.

Every district operates independently with its own elected board and its own employee labor contracts. Each has taken a different approach as state revenues have been cut. Many have spent down reserves and asked employees to take unpaid furlough days. Some opted to take on larger class sizes.

“They all have different ways they have to deal with budget cuts,” said Lora Duzyk, assistant superintendent of business services with the county Office of Education. “We’ve been in this crisis five years. They all look at it and deal with it differently.”

Under state law, districts must issue layoff warnings by a March 15 deadline. They must formally issue or rescind the notices by May 15.

San Diego Unified plans to lay off 1,656 of its 7,000 teachers for the 2012-13 school year.

The remainder of the more than 500 pink slips in the county are divided among 18 districts, including the Sweetwater Union High School District, which plans to lay off 211 teachers and Carlsbad Unified, which is issuing 106 layoff notices. The county Office of Education is also planning layoffs.

Gov. Jerry Brown is asking voters for a tax increase in November, which would ease the education funding crunch. But districts are building their budgets as if the ballot measure doesn’t pass.

Some of the districts not laying off teachers next year went through teacher cutbacks previously. Some have been able to avoid layoffs entirely.

For example, the La Mesa-Spring Valley School District, which employs about 600 teachers, laid off about 150 teachers over the past three years. Its teachers also agreed to take nine furlough days, the equivalent of a 4.5 percent salary reduction, which saved about $3.2 million.

“We did some pretty heavy lifting last year,” Superintendent Brian Marshall said. “We laid off about 103 teachers as well as classified staff. This year, I really can’t lay off teachers because I’m at the maximum class size.”

Escondido Union, which has 967 teachers, decided not to do any layoffs after making continual cuts over the past several years, including laying off about 65 teachers and raising its K-3 class sizes from 20 to 24.5 students, Superintendent Jennifer Walters said.

The district reduced some of its employee health benefits and had every employee take four furlough days for the past two years, which saved the district $2 million a year, she said. It plans to tap reserves to cover any budget shortfalls.

“In our district, we call it a year of reprieve and we can face that reality in November,” Walters said.

Poway school board member Penny Rantfle said even though her district isn’t issuing any pink slips — and hasn’t laid off a teacher in recent years — the budget cuts have taken a toll in Poway classrooms. Its K-3 classes, which used to have a maximum of 20 students, now have 27, and fourth- and fifth-grade classes are about 33 students.

“I’d like you to come visit our schools and visit those algebra classes where there are 41 and 42 students in a classroom,” Rantfle said. “There are very real consequences for us and more importantly for our children. Every school district is doing things a little bit differently — but that’s my story and it’s a tragedy.”

Poway offered retirement incentives three years ago, prompting more than 100 employees to retire. It also cut its school year by five days and reduced professional development by three days in 2010 as part of a negotiated agreement with its teachers union, which produced $10 million in savings over two years. The agreement expires June 30.

The Chula Vista Elementary School District is not issuing any pink slips to teachers this year and has not laid off a teacher in the past five years. In recent years, the district has tapped its large pool of reserves to make up for budget shortfalls.

Administrators, teachers and other staff also took furlough days, which saved the district $4 million annually. Average class sizes have inched up, with K-3 nearing 24 students per teacher.

“The willingness of bargaining groups to preserve jobs is what it boiled down to,” said district spokesman Anthony Millican. “We are grateful to our bargaining groups for seeing us through what we believed was the hardest stretch. Of course, come November if that tax initiative (fails), then we are back at the table. I think a lot of districts will be re-evaluating their options.”

Because more than 80 percent of a school district’s budget typically goes toward salaries and benefits, some districts say they have run out of options other than cutting personnel.

Contributing to San Diego Unified’s budget woes this year are negotiated pay raises set to go into effect June 30. After its teachers worked without a contract for nearly two years, the district in 2010 promised employees 7 percent raises in the 2012-13 school year if they agreed to two years of furloughs. Those raises are estimated to cost the district $21 million in 2012-13 and $43 million in 2013-14. Undoing furlough days will cost the district $17 million per year.

No other large school district in the region is poised to give its employees raises next year, Duzyk said.

The San Diego school board has been pushing for $50 million in concessions, asking the unions to forgo the raises, extend furlough days for a third year and to pay more for health insurance.

“In previous years, we’ve tried to keep our cuts as far away from the classroom as possible and to keep our class sizes as low as possible” in hopes that state revenues would be forthcoming, said Bernie Rhinerson, the district’s chief of staff. “The crisis has lasted longer than anyone expected. So now we are at a point where we have to make these reductions to our teaching staff in order to balance the budget or we have to have concessions from our employees in order to reduce layoffs.”

Last year, San Diego Unified issued 1,350 layoff notices only to recall 90 percent of them, bringing back the majority of teachers in order to preserve class sizes.

“Forty-two school districts have 42 different cultures, governance, histories and how you got to this point (is different),” Superintendent Bill Kowba said. “Poway mentioned they had 41 kids in an algebra classroom. We postponed that to the absolute last moment, but we will be there next year. We are all going to get to the same destination.”